Go Back   The Ford Barn > General Discussion > Model A (1928-31)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 03-13-2019, 08:41 PM   #1
bill boz
Junior Member
 
Join Date: Apr 2014
Posts: 13
Default Mitchell transmission or overdrive

I would like to improve the drivability of my 31 closed cab pickup. Originally I was thinking about a Mitchell overdrive but now I’m wondering if I would be better off with the Mitchell synchromesh transmission. The truck has a strong engine and 3.56 rear end and 19 inch wheels. Most of our touring is at 45 to 50 we seldom run much higher. Our terrain is flat to rolling hills. My thinking is that the 3.56 rear end gets us going fast enough, seems like it would be great to have the easy up and down shifting from a synchronized transmission. I know this transmission is only synchronized in 2nd and 3rd gears that’s what I’m used to with my 40’s vintage cars. I wonder about your experience with either the transmission or overdrive and what other factors I might be overlooking. I have read as many past threads as I could find and am still pondering.

Thanks
Bill

Last edited by bill boz; 03-14-2019 at 06:42 AM.
bill boz is offline   Reply With Quote
Old 03-13-2019, 09:14 PM   #2
Railcarmover
BANNED
 
Join Date: Apr 2017
Location: Sacramento
Posts: 1,262
Default Re: Mitchell transmission or overdrive

Buy the overdrive..actually its a splitter box,the first time your wring out second low and shift to second high you'll be sold.
Railcarmover is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 03-13-2019, 09:27 PM   #3
Synchro909
Senior Member
 
Synchro909's Avatar
 
Join Date: Jun 2014
Location: Melbourne, Australia
Posts: 7,471
Default Re: Mitchell transmission or overdrive

I have one car with both the MItchell transmission and O/D. We do lots of miles towing a camper behind that one. I have another 3 cars and all of those have the original cog house and a Mitchell O/D (gear splitter). One of those also has a 3.54 rear end (1928 Tudor) with a B engine fitted with a downdraught carby. That car doesn't handle hills all that well but I can sit on 60 mph easily enough in it on the flat. I think I prefer the standard rear end with O/D. The original gearbox is fine.
In your case, I'd go the O/D
__________________
I'm part of the only ever generation with an analogue childhood and a digital adulthood.
Synchro909 is offline   Reply With Quote
Old 03-13-2019, 10:57 PM   #4
Dick Steinkamp
Senior Member
 
Dick Steinkamp's Avatar
 
Join Date: Apr 2016
Location: Bellingham, WA
Posts: 1,163
Default Re: Mitchell transmission or overdrive

Quote:
Originally Posted by bill boz View Post
I know this transmission is only synchronized in 1st and 2nd gears ...
I think you mean 2nd and 3rd.
__________________
All steel from pedal to wheel
Dick Steinkamp is offline   Reply With Quote
Old 03-14-2019, 12:11 AM   #5
CarlG
Senior Member
 
CarlG's Avatar
 
Join Date: Nov 2010
Location: Anchorage, Alaska
Posts: 9,109
Default Re: Mitchell transmission or overdrive

I have the F150 OD with 3.78 rear. This gives me Synchronized gears plus OD. Does very well on the flat or hills.
__________________
Alaskan A's
Antique Auto Mushers of Alaska
Model A Ford Club of America
Model A Restorers Club
Antique Automobile Club of America
Mullins Owner's Club
CarlG is offline   Reply With Quote
Old 03-14-2019, 04:41 AM   #6
SAJ
Senior Member
 
SAJ's Avatar
 
Join Date: Jul 2010
Location: Auckland, New Zealand
Posts: 513
Default Re: Mitchell transmission or overdrive

Sponsored Links (Register now to hide all advertisements)
We have a 31 Tudor with a strong engine, Mitchell overdrive 26% and Mitchell gearbox with 15% higher 1st and second. Diff is 3.78 and tyres are 16 inch on V8 rims.
This is a nice car to drive, but every now and then on really steep 180 degree uphill bends needs first gear to avoid straining. On the other hand on long uphill pulls in the hills where top gear is too high, overdrive second really speeds things up.
Our Roadster with a very strong engine cannot go as fast up these hills where second gear is needed without going over my 2600 rev limit. But it pulls the very tight uphill bends in second gear ok. It has 19 inch wheels with Excelsior sport radials 155X19. Gearbox is standard Model A, overdrive is 26% Mitchell and rear end 3.78.
Both are a delight to drive and impossible to say which is best.
Reading this to myself I think the message is stay with 3.78, put in 26% Mitchell o/d and if your gearbox needs any kind of attention put in the Mitchell synchro internals. For a strong engine ( higher compression, better camshaft, larger carb.) go for higher first and second gear ratios. For a standard engine I am not sure on this last point. One can up the ratio on either or none of first and second gears.
I put a plus 15% first and second in a friends cabriolet with standard diff and tyres. His only comment is "it goes very fast in reverse now, especially in backing out of my shed". He is 85 and a rather slow driver.
SAJ in NZ

Last edited by SAJ; 03-14-2019 at 03:51 PM. Reason: Changed 12% to15%
SAJ is online now   Reply With Quote
Old 03-14-2019, 06:41 AM   #7
1929
Senior Member
 
Join Date: Jan 2015
Location: New York
Posts: 943
Default Re: Mitchell transmission or overdrive

I have the 3.54 rear with the Mitchell synchro tranny, was going to get the overdrive, but don't think its needed since I just cruise at 60mph.
1929 is offline   Reply With Quote
Old 03-14-2019, 09:08 AM   #8
Mike Peters
Senior Member
 
Mike Peters's Avatar
 
Join Date: Aug 2012
Location: South East Wisconsin
Posts: 1,279
Default Re: Mitchell transmission or overdrive

I ordered a 26% Mitchell two weeks ago for our Tudor with stock 3.78 rear end gearing. . I've had an old Borg Warner overdrive in the car since the late 1980's. Last fall the Borg Warner made a terrible clunk and then nothing. Permanent neutral. Tow truck ride back home. No more Borgs for us. Thanks for the great info guys! Makes me feel good about ordering a Mitchell.
Mike Peters is offline   Reply With Quote
Old 03-14-2019, 09:13 AM   #9
Ray in La Mesa
Senior Member
 
Join Date: May 2010
Location: La Mesa Ca
Posts: 1,157
Default Re: Mitchell transmission or overdrive

Have a 36% Mitchel for the cabriolet but also have a cut down Columbia in the '28 pickup with 3.78's and REALLY like being able to split the gears.
Ray in La Mesa is offline   Reply With Quote
Old 03-14-2019, 03:24 PM   #10
bill boz
Junior Member
 
Join Date: Apr 2014
Posts: 13
Default Re: Mitchell transmission or overdrive

Quote:
Originally Posted by 1929 View Post
I have the 3.54 rear with the Mitchell synchro tranny, was going to get the overdrive, but don't think its needed since I just cruise at 60mph.
Did you opt for th 15% higher 1st and 2nd gear?
Thanks
bill boz is offline   Reply With Quote
Old 03-14-2019, 04:03 PM   #11
Synchro909
Senior Member
 
Synchro909's Avatar
 
Join Date: Jun 2014
Location: Melbourne, Australia
Posts: 7,471
Default Re: Mitchell transmission or overdrive

Quote:
Originally Posted by 1929 View Post
I have the 3.54 rear with the Mitchell synchro tranny, was going to get the overdrive, but don't think its needed since I just cruise at 60mph.
I'm sure I wouldn't be driving at that speed even with the higher ratio diff and without an O/D.
__________________
I'm part of the only ever generation with an analogue childhood and a digital adulthood.
Synchro909 is offline   Reply With Quote
Old 03-14-2019, 05:44 PM   #12
Dick Steinkamp
Senior Member
 
Dick Steinkamp's Avatar
 
Join Date: Apr 2016
Location: Bellingham, WA
Posts: 1,163
Default Re: Mitchell transmission or overdrive

A Model A has so much torque (125 ft lbs) relative to its weight that I can't see how splitting gears would be an advantage. The owner's manual wants you to get into high gear at 12 MPH.

I also agree that being able to cruise at 60 and better is not something that I would do without a modern brake and tire upgrade.

These are great cars, but they have their limits.
__________________
All steel from pedal to wheel
Dick Steinkamp is offline   Reply With Quote
Old 03-14-2019, 05:50 PM   #13
1929
Senior Member
 
Join Date: Jan 2015
Location: New York
Posts: 943
Default Re: Mitchell transmission or overdrive

Quote:
Originally Posted by bill boz View Post
Did you opt for th 15% higher 1st and 2nd gear?
Thanks
I don't remember, it was 4 years ago, I just did what the Mitchells recommended. The receipt says ratio #3.
1929 is offline   Reply With Quote
Old 03-14-2019, 05:52 PM   #14
1929
Senior Member
 
Join Date: Jan 2015
Location: New York
Posts: 943
Default Re: Mitchell transmission or overdrive

Quote:
Originally Posted by Synchro909 View Post
I'm sure I wouldn't be driving at that speed even with the higher ratio diff and without an O/D.
Iam under 3000rpms at 60
1929 is offline   Reply With Quote
Old 03-14-2019, 05:55 PM   #15
1929
Senior Member
 
Join Date: Jan 2015
Location: New York
Posts: 943
Default Re: Mitchell transmission or overdrive

Quote:
Originally Posted by Dick Steinkamp View Post
A Model A has so much torque (125 ft lbs) relative to its weight that I can't see how splitting gears would be an advantage. The owner's manual wants you to get into high gear at 12 MPH.

I also agree that being able to cruise at 60 and better is not something that I would do without a modern brake and tire upgrade.

These are great cars, but they have their limits.
Dick, my 16s stop on the dime, with all new brakes and good thick shoes from Randy.
1929 is offline   Reply With Quote
Old 03-14-2019, 06:23 PM   #16
whirnot
Senior Member
 
whirnot's Avatar
 
Join Date: Mar 2013
Location: Bend Or.
Posts: 1,053
Default Re: Mitchell transmission or overdrive

If you do go with just the tranny, consider instead of a higher 1st and second, go with just the second. First is pretty high, especially for parades etc. Then there is a big jump to third. We opted to keep 1st as it is then a 15 percent higher second. Initial test drive, we liked it but winter hit before we could test it much.
__________________
Bill Worden

1929 Roadster
1929 Briggs Town Sedan
1930 Closed Cab pickup
Smith Motor Compressor
1951 Ford F1

High Desert Model A's
whirnot is offline   Reply With Quote
Old 03-14-2019, 11:34 PM   #17
The Master Cylinder
Senior Member
 
The Master Cylinder's Avatar
 
Join Date: Aug 2012
Posts: 875
Default Re: Mitchell transmission or overdrive

Bill, Is this with your Roadster or Town Sedan?
__________________
The Master Cylinder

Enjoying life at the beach in SoCal...
The Master Cylinder is offline   Reply With Quote
Old 03-14-2019, 11:41 PM   #18
The Master Cylinder
Senior Member
 
The Master Cylinder's Avatar
 
Join Date: Aug 2012
Posts: 875
Default Re: Mitchell transmission or overdrive

Quote:
Originally Posted by 1929 View Post
I am under 3000rpms at 60
Can we assume your engine is not stock? 3000 rpm is pretty high for a Model A engine.
__________________
The Master Cylinder

Enjoying life at the beach in SoCal...
The Master Cylinder is offline   Reply With Quote
Old 03-15-2019, 01:10 AM   #19
whirnot
Senior Member
 
whirnot's Avatar
 
Join Date: Mar 2013
Location: Bend Or.
Posts: 1,053
Default Re: Mitchell transmission or overdrive

Quote:
Originally Posted by The Master Cylinder View Post
Bill, Is this with your Roadster or Town Sedan?
That is in the roadster.
__________________
Bill Worden

1929 Roadster
1929 Briggs Town Sedan
1930 Closed Cab pickup
Smith Motor Compressor
1951 Ford F1

High Desert Model A's
whirnot is offline   Reply With Quote
Old 03-15-2019, 06:19 AM   #20
1929
Senior Member
 
Join Date: Jan 2015
Location: New York
Posts: 943
Default Re: Mitchell transmission or overdrive

Quote:
Originally Posted by The Master Cylinder View Post
Can we assume your engine is not stock? 3000 rpm is pretty high for a Model A engine.
Inserts, 6-1 Head, Ross forged pistons,counterbalanced crankshaft,lightened flywheel, etc.
1929 is offline   Reply With Quote
Old 03-15-2019, 06:47 AM   #21
Smitty
Senior Member
 
Smitty's Avatar
 
Join Date: May 2010
Location: Boston North Shore
Posts: 750
Default Re: Mitchell transmission or overdrive

I have been running a Mitchell Overdrive and 3:54 rear end gears in my coupe for a number of years. Great combo, recently had a Mitchell Transmission built but have not yet installed.
The overdrive/second is a sweet-spot for pulling hills where just second gear is too low.
Smitty is offline   Reply With Quote
Old 03-15-2019, 07:50 AM   #22
jhowes
Senior Member
 
Join Date: Jul 2010
Location: upstate NY near Mass border
Posts: 789
Default Re: Mitchell transmission or overdrive

I have a 30's car because I enjoy traveling at 45 mph. If I wanted to go 60, then I would opt for a 50's car. I find that the 3.54 rear makes a nice drivable, near stock, car a pleasure to drive. Someone on here says that "speed is expensive, how fast do you want to go. I would add that speed kills when do you want to go. Jack
jhowes is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 03-15-2019, 08:17 AM   #23
Railcarmover
BANNED
 
Join Date: Apr 2017
Location: Sacramento
Posts: 1,262
Default Re: Mitchell transmission or overdrive

Updating a model a to compete with today's drivers and road conditions is a challenge.To prove the car is still viable by modifying the original components is my goal with one.In no way is this an indictment of the car in stock form,we are here due to its enduring beauty.Geographic location often determines if you can enjoy your car stock,or modified..rural folks can do just about anything at 45,city folks have different demands based on conditions.Modifiers are not hotrodders..
Railcarmover is offline   Reply With Quote
Old 03-15-2019, 09:15 AM   #24
1929
Senior Member
 
Join Date: Jan 2015
Location: New York
Posts: 943
Default Re: Mitchell transmission or overdrive

Quote:
Originally Posted by Railcarmover View Post
Updating a model a to compete with today's drivers and road conditions is a challenge.To prove the car is still viable by modifying the original components is my goal with one.In no way is this an indictment of the car in stock form,we are here due to its enduring beauty.Geographic location often determines if you can enjoy your car stock,or modified..rural folks can do just about anything at 45,city folks have different demands based on conditions.Modifiers are not hotrodders..
Exactly, in New York, no respect for the Model A on these roads.
1929 is offline   Reply With Quote
Old 03-15-2019, 04:48 PM   #25
updraught
Senior Member
 
updraught's Avatar
 
Join Date: Feb 2015
Location: Australia
Posts: 1,966
Default Re: Mitchell transmission or overdrive

Final drive standard is 3.78:1 and second gear about 7:1.

At some speed you will likely be out of the power band in either gear.
updraught is offline   Reply With Quote
Old 03-15-2019, 07:48 PM   #26
Railcarmover
BANNED
 
Join Date: Apr 2017
Location: Sacramento
Posts: 1,262
Default Re: Mitchell transmission or overdrive

Sponsored Links (Register now to hide all advertisements)
Quote:
Originally Posted by 1929 View Post
Exactly, in New York, no respect for the Model A on these roads.
grew up in Islip,know all about that..out here you get the same stuff,now mixed with someone who is traveling 70 mph completely distracted by their phone
Railcarmover is offline   Reply With Quote
Old 03-16-2019, 09:29 PM   #27
bill boz
Junior Member
 
Join Date: Apr 2014
Posts: 13
Default Re: Mitchell transmission or overdrive

Thank you all for your thoughtful responses they have given me a lot to think about. To the mix there is also the f150 4 speed conversion, it would be easy if there was only one choice. If I can ever come to a decision I’ll post the result.
Bill
bill boz is offline   Reply With Quote
Old 03-16-2019, 11:54 PM   #28
mreman
Member
 
mreman's Avatar
 
Join Date: Sep 2013
Location: Temple City, CA.
Posts: 34
Default Re: Mitchell transmission or overdrive

I have a coupe with a B engine and trans with synchros and a Laycock Overdrive; It handals flat and hills very well; I also have a sedan .an A engine dn draft weber and high compression head and a Laycock Overdrive with a 39 trans . Both cars are fun easy drivers with 3.78 rear ends and 600-16 wheels.
Some diff from Mitchell, when you want to shift into OD you just flip a switch on your gearshift and the same dn shifting from OD to 3rd. No clutch is required and your thrust bearings are minimized for wear.
As for cons on the Laycock the biggest is you have to come out of OD before you put it in reverse or you can damage it. My Sedan with the 39 has a switch built on the Trans to cut out the OD when you put it into reverse; the Coupe does not have that feature.
mreman is offline   Reply With Quote
Old 03-18-2019, 10:32 PM   #29
31a
Senior Member
 
Join Date: Jun 2010
Location: College Station, Tx
Posts: 326
Default Re: Mitchell transmission or overdrive

I run a 6.1 with the Mitchell 26 % in my 4door works very well hills or flat would recommend I have 2 other A s with mitchells these are stock heads and work well also
31a is offline   Reply With Quote
Old 03-24-2019, 10:45 AM   #30
Smitty
Senior Member
 
Smitty's Avatar
 
Join Date: May 2010
Location: Boston North Shore
Posts: 750
Default Re: Mitchell transmission or overdrive

The advantage with a Mitchell OD is not only a factor of speed but more importantly to smooth and quiet the motor. I found the Mitchell to be better balanced of the drive-line even when not traveling in overdrive. Also the motor does not "wind-up" so much when in OD, even at lower speeds. Quiets the motor and improves fuel economy.
Smitty is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 05:36 AM.